Certain medical and technical applications utilize an ability to look inside the patient's body or use a particular device when the available pathways for probe advancement are of very narrow diameter (e.g., small vessels, small ducts, small needles, cracks etc.).
Conventional miniature endoscopes are generally composed of fiber-optic imaging bundles. These conventional instruments have diameters that range of from approximately 250 μm to 1.0 mm. Since optical fibers have a finite diameter, a limited number of fibers can be incorporated into one imaging bundle, resulting in a limited number of resolvable elements. The resultant image resolution and field of view provided by these imaging devices may be insufficient for obtaining endoscopic images of diagnostic quality in patients. The use of multiple fibers for imaging also increases the rigidity of the endoscopes, likely resulting in a bend radius of approximately 5 cm for the smallest probes in a clinical use. These technical limitations of fiber bundle microendoscopes, including a low number of resolvable points and increased rigidity, have limited the widespread use of miniature endoscopy in medicine.
U.S. Pat. No. 6,134,003 describes spectrally encoded endoscopy (“SEE”) techniques and arrangements which facilitate the use of a single optical fiber to transmit one-dimensional (e.g., line) image by spectrally encoding one spatial axis. By mechanically scanning this image line in the direction perpendicular thereto, a two dimensional image of the scanned plane can be obtained outside of the probe. This conventional technology provides a possibility for designing the probes that are of slightly bigger diameter than an optical fiber. Probes in approximately 100 μm diameter range may be developed using such SEE technology.
SEE techniques and systems facilitate a simultaneous detection of most or all points along a one-dimensional line of the image. Encoding the spatial information on the sample can be accomplished by using a broad spectral bandwidth light source as the input to a single optical fiber endoscope.
FIG. 1 shows one such exemplary SEE system/probe 100. For example, at a distal end of the exemplary system/probe 100, light provided by the source can be transmitted via an optical fiber 110, and collimated by a collimating lens 120. Further, the source spectrum of the light can be dispersed by a dispersing element 130 (e.g., a diffracting grating), and focused by a lens 140 onto the sample. This optical configuration can provide an illumination of the sample with an array of focused spots 150 (e.g., on a wavelength-encoded axis), where each position (e.g., on the x-axis) can be encoded by a different wavelength (1). Following the transmission back through the optical fiber, the reflectance as a function of transverse location can be determined by measuring the reflected spectrum. High-speed spectral detection can occur externally to the probe and, as a result, the detection of one line of image data may not necessarily increase the diameter of the exemplary system/probe 100. The other dimension (e.g., y, slow scan axis) of the image can be obtained by mechanically scanning the optical fiber and distal optics at a slower rate.
Accordingly, it may be beneficial to address and/or overcome at least some of the deficiencies described herein above.